scholarly journals The contribution of marine organics to the air quality of the western United States

2010 ◽  
Vol 10 (15) ◽  
pp. 7415-7423 ◽  
Author(s):  
B. Gantt ◽  
N. Meskhidze ◽  
A. G. Carlton
Keyword(s):  
United States ◽  
Air Quality ◽  
San Francisco ◽  
Atmospheric Chemistry ◽  
Environmental Protection Agency ◽  
Regional Scale ◽  
The United States ◽  
Coastal Areas ◽  
Western United States ◽  
The Us

Abstract. The contribution of marine organic emissions to the air quality in coastal areas of the western United States is studied using the latest version of the US Environmental Protection Agency (EPA) regional-scale Community Multiscale Air Quality (CMAQv4.7) modeling system. Emissions of marine isoprene, monoterpenes, and primary organic matter (POM) from the ocean are implemented into the model to provide a comprehensive view of the connection between ocean biology and atmospheric chemistry and air pollution. Model simulations show that marine organics can increase the concentration of PM2.5 by 0.1–0.3 μg m−3 (up to 5%) in some coastal cities such as San Francisco, CA. This increase in the PM2.5 concentration is primarily attributed to the POM emissions, with small contributions from the marine isoprene and monoterpenes. When marine organic emissions are included, organic carbon (OC) concentrations over the remote ocean are increased by up to 50% (25% in coastal areas), values consistent with recent observational findings. This study is the first to quantify the air quality impacts from marine POM and monoterpenes for the United States, and it highlights the need for inclusion of marine organic emissions in air quality models.

scholarly journals The impact of marine organics on the air quality of the western United States

2010 ◽  
Vol 10 (3) ◽  
pp. 6257-6278 ◽  
Author(s):  
B. Gantt ◽  
N. Meskhidze ◽  
A. G. Carlton
Keyword(s):  
United States ◽  
Air Quality ◽  
Atmospheric Chemistry ◽  
Environmental Protection Agency ◽  
Regional Scale ◽  
The United States ◽  
Coastal Areas ◽  
Western United States ◽  
The Us ◽  
The Impact

Abstract. The impact of marine organic emissions to the air quality in coastal areas of the western United States is studied using the latest version of the US Environmental Protection Agency (EPA) regional-scale Community Multiscale Air Quality (CMAQv4.7) modeling system. Emissions of marine isoprene, monoterpenes, and primary organic matter (POM) from the ocean are implemented into the model to provide a comprehensive view of the connection between ocean biology and atmospheric chemistry and air pollution. Model simulations show that marine organics can increase the concentration of PM2.5 by 0.1–0.3 μg m−3 (up to 5%) in coastal cities. This increase in the PM2.5 concentration is primarily attributed to the POM emissions, with small contributions from the marine isoprene and monoterpenes. When marine organic emissions are included, organic carbon (OC) concentrations over the remote ocean are increased by up to 50% (25% in coastal areas), values consistent with recent observational findings. This study is the first to quantify the air quality impacts from marine POM and monoterpenes for the United States, and highlights the need for inclusion of marine organic emissions in air quality models.

scholarly journals Continued emissions of carbon tetrachloride from the United States nearly two decades after its phaseout for dispersive uses

2016 ◽  
Vol 113 (11) ◽  
pp. 2880-2885 ◽  
Author(s):  
Lei Hu ◽  
Stephen A. Montzka ◽  
Ben R. Miller ◽  
Arlyn E. Andrews ◽  
John B. Miller ◽  
...  
Keyword(s):  
United States ◽  
Carbon Tetrachloride ◽  
San Francisco ◽  
Environmental Protection Agency ◽  
Gulf Coast ◽  
The United States ◽  
Bay Area ◽  
The Us ◽  
Atmospheric Observations ◽  
Surrounding Areas

National-scale emissions of carbon tetrachloride (CCl4) are derived based on inverse modeling of atmospheric observations at multiple sites across the United States from the National Oceanic and Atmospheric Administration’s flask air sampling network. We estimate an annual average US emission of 4.0 (2.0–6.5) Gg CCl4 y−1 during 2008–2012, which is almost two orders of magnitude larger than reported to the US Environmental Protection Agency (EPA) Toxics Release Inventory (TRI) (mean of 0.06 Gg y−1) but only 8% (3–22%) of global CCl4 emissions during these years. Emissive regions identified by the observations and consistently shown in all inversion results include the Gulf Coast states, the San Francisco Bay Area in California, and the Denver area in Colorado. Both the observation-derived emissions and the US EPA TRI identified Texas and Louisiana as the largest contributors, accounting for one- to two-thirds of the US national total CCl4 emission during 2008–2012. These results are qualitatively consistent with multiple aircraft and ship surveys conducted in earlier years, which suggested significant enhancements in atmospheric mole fractions measured near Houston and surrounding areas. Furthermore, the emission distribution derived for CCl4 throughout the United States is more consistent with the distribution of industrial activities included in the TRI than with the distribution of other potential CCl4 sources such as uncapped landfills or activities related to population density (e.g., use of chlorine-containing bleach).

scholarly journals The case for Pacific media reform to reflect island communities

2005 ◽  
Vol 11 (1) ◽  
pp. 26-35
Author(s):  
Kalafi Moala
Keyword(s):  
United States ◽  
San Francisco ◽  
San Francisco Bay ◽  
San Francisco Bay Area ◽  
The United States ◽  
Daily News ◽  
Bay Area ◽  
The Us ◽  
Island Communities ◽  
The Media

"The largest number of Tongans outside of Tonga lives in the United States. It is estimated to be more than 70,000; most live in the San Francisco Bay Area. On several occasions during two visits to the US by my wife and I during 2004, we met workers who operate the only daily Tongan language radio programmes in San Francisco. Our organisation supplies the daily news broadcast for their programmes. Our newspapers— in the Tongan and Samoan languages— also sell in the area. The question of what are the fundamental roles of the media came up in one of our discussions..."

scholarly journals Perceived Neighborhood-level Drivers of Food Insecurity Among Aging Women in the United States (P04-155-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Jacqueline Shieh ◽  
Sheri Weiser ◽  
Henry Whittle ◽  
Ighovwerha Ofotokun ◽  
Adaora Adimora ◽  
...  
Keyword(s):  
United States ◽  
Chronic Illness ◽  
Food Insecurity ◽  
San Francisco ◽  
The United States ◽  
Food Stores ◽  
Chapel Hill ◽  
Aging Women ◽  
The Us ◽  
Neighborhood Level

Abstract Objectives Aging populations in the United States (US) exhibit high rates of both food insecurity and chronic illness. Few studies have explored in depth how food insecurity arises among such populations, and how it interacts with experiences of aging. We qualitatively explored how aging, low-income women experience food insecurity at multiple sites across the US, focusing on the neighborhood-level factors that influence these experiences. Methods Study participants were drawn from the San Francisco, CA, Atlanta, GA, and Chapel Hill, NC sites of the Women's Interagency HIV Study (WIHS), a cohort study of women with or at risk for HIV. Using purposive sampling, we recruited 38 women who were food-insecure, 50 years of age or older, either with or at risk for HIV, and from different neighborhoods within each site. Semi-structured interviews explored participants’ perceptions of how their neighborhood influenced their experiences with food security and aging. An inductive-deductive approach was used to thematically analyze the data. Results Participants across the three sites explained that food insecurity was related to limited access to food stores. In San Francisco, this limited access primarily resulted from high food prices, whereas in Atlanta and Chapel Hill long distances to food stores and poor public transport systems were prominent. Most participants also described being dependent on food aid programs, but often found this difficult due to poor quality food and long wait times. Aging-related issues emerged as a cross-cutting theme. Both HIV + and HIV- women explained how fatigue, poor strength, and joint pains all amplified their barriers to accessing food. Women with chronic illness, regardless of HIV status, also found it difficult to afford healthy and nutritious food, which in turn further aggravated their poor health. Conclusions Findings from this study suggest that older women across different settings in the US experience multiple barriers to navigating the food system, with key similarities and differences in barriers and systems of institutional support. While future programs should address common neighborhood-level barriers such as the availability and affordability of healthy foods and transportation, they should also be tailored to aging women, and to the unique local context. Funding Sources NIAID.

Linking the Eta Model with the Community Multiscale Air Quality (CMAQ) Modeling System to Build a National Air Quality Forecasting System

2005 ◽  
Vol 20 (3) ◽  
pp. 367-384 ◽  
Author(s):  
Tanya L. Otte ◽  
George Pouliot ◽  
Jonathan E. Pleim ◽  
Jeffrey O. Young ◽  
Kenneth L. Schere ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Environmental Protection Agency ◽  
Rural Areas ◽  
Numerical Models ◽  
The United States ◽  
Air Quality Forecast ◽  
Eta Model ◽  
State And Local ◽  
Air Quality Forecasting

Abstract NOAA and the U.S. Environmental Protection Agency (EPA) have developed a national air quality forecasting (AQF) system that is based on numerical models for meteorology, emissions, and chemistry. The AQF system generates gridded model forecasts of ground-level ozone (O3) that can help air quality forecasters to predict and alert the public of the onset, severity, and duration of poor air quality conditions. Although AQF efforts have existed in metropolitan centers for many years, this AQF system provides a national numerical guidance product and the first-ever air quality forecasts for many (predominantly rural) areas of the United States. The AQF system is currently based on NCEP’s Eta Model and the EPA’s Community Multiscale Air Quality (CMAQ) modeling system. The AQF system, which was implemented into operations at the National Weather Service in September of 2004, currently generates twice-daily forecasts of O3 for the northeastern United States at 12-km horizontal grid spacing. Preoperational testing to support the 2003 and 2004 O3 forecast seasons showed that the AQF system provided valuable guidance that could be used in the air quality forecast process. The AQF system will be expanded over the next several years to include a nationwide domain, a capability for forecasting fine particle pollution, and a longer forecast period. State and local agencies will now issue air quality forecasts that are based, in part, on guidance from the AQF system. This note describes the process and software components used to link the Eta Model and CMAQ for the national AQF system, discusses several technical and logistical issues that were considered, and provides examples of O3 forecasts from the AQF system.

scholarly journals Development and application of a United States-wide correction for PM<sub>2.5</sub> data collected with the PurpleAir sensor

2021 ◽  
Vol 14 (6) ◽  
pp. 4617-4637
Author(s):  
Karoline K. Barkjohn ◽  
Brett Gantt ◽  
Andrea L. Clements
Keyword(s):  
United States ◽  
Air Quality ◽  
Reference Method ◽  
Ambient Air ◽  
The United States ◽  
Global Network ◽  
Raw Data ◽  
The Us ◽  
State And Local ◽  
Multiplicative Models

Abstract. PurpleAir sensors, which measure particulate matter (PM), are widely used by individuals, community groups, and other organizations including state and local air monitoring agencies. PurpleAir sensors comprise a massive global network of more than 10 000 sensors. Previous performance evaluations have typically studied a limited number of PurpleAir sensors in small geographic areas or laboratory environments. While useful for determining sensor behavior and data normalization for these geographic areas, little work has been done to understand the broad applicability of these results outside these regions and conditions. Here, PurpleAir sensors operated by air quality monitoring agencies are evaluated in comparison to collocated ambient air quality regulatory instruments. In total, almost 12 000 24 h averaged PM2.5 measurements from collocated PurpleAir sensors and Federal Reference Method (FRM) or Federal Equivalent Method (FEM) PM2.5 measurements were collected across diverse regions of the United States (US), including 16 states. Consistent with previous evaluations, under typical ambient and smoke-impacted conditions, the raw data from PurpleAir sensors overestimate PM2.5 concentrations by about 40 % in most parts of the US. A simple linear regression reduces much of this bias across most US regions, but adding a relative humidity term further reduces the bias and improves consistency in the biases between different regions. More complex multiplicative models did not substantially improve results when tested on an independent dataset. The final PurpleAir correction reduces the root mean square error (RMSE) of the raw data from 8 to 3 µg m−3, with an average FRM or FEM concentration of 9 µg m−3. This correction equation, along with proposed data cleaning criteria, has been applied to PurpleAir PM2.5 measurements across the US on the AirNow Fire and Smoke Map (https://fire.airnow.gov/, last access: 14 May 2021) and has the potential to be successfully used in other air quality and public health applications.

scholarly journals The impact of monthly variation of the Pacific-North America (PNA) teleconnection pattern on wintertime surface-layer aerosol concentrations in the United States

2015 ◽  
Vol 15 (22) ◽  
pp. 33209-33251
Author(s):  
J. Feng ◽  
H. Liao ◽  
J. Li
Keyword(s):  
United States ◽  
Surface Layer ◽  
Air Quality ◽  
North America ◽  
Organic Carbon ◽  
Black Carbon ◽  
The United States ◽  
Monthly Variation ◽  
The Pacific ◽  
The Us

Abstract. The Pacific-North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variation of the PNA phase (positive or negative phase) on wintertime surface-layer aerosol concentrations in the US by analyzing observations during 1999–2013 from the Air Quality System of Environmental Protection Agency (EPA-AQS) and the model results for 1986–2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999–2003 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon aerosols over the US were higher in the PNA positive phases than in the PNA negative phases by 1.4 μg m−3 (12.7 %), 0.1 μg m−3 (6.4 %), 0.3 μg m−3 (39.1 %), 0.2 μg m−3 (22.8 %), 0.8 μg m−3 (21.3 %), and 0.2 μg m−3 (34.1 %), respectively. The simulated geographical patterns of the differences in concentrations of all aerosol species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation driven by the assimilated meteorological fields, the PNA-induced variation in planetary boundary layer height was found to be the most dominant meteorological factor that influenced the concentrations of PM2.5, sulfate, ammonium, organic carbon, and black carbon, and the PNA-induced variation in temperature was the most important parameter that influenced nitrate aerosol. Results from this work have important implications for understanding and prediction of air quality in the United States.

scholarly journals How emissions, climate, and land use change will impact mid-century air quality over the United States: a focus on effects at National Parks

2014 ◽  
Vol 14 (19) ◽  
pp. 26495-26543 ◽  
Author(s):  
M. Val Martin ◽  
C. L. Heald ◽  
J.-F. Lamarque ◽  
S. Tilmes ◽  
L. K. Emmons ◽  
...  
Keyword(s):  
United States ◽  
Land Use ◽  
Air Quality ◽  
National Parks ◽  
Land Use Changes ◽  
The United States ◽  
Western Us ◽  
The Us ◽  
Us Epa ◽  
Surface O3

Abstract. We use a global coupled chemistry-climate-land model (CESM) to assess the integrated effect of climate, emissions and land use changes on annual surface O3 and PM2.5 on the United States with a focus on National Parks (NPs) and wilderness areas, using the RCP4.5 and RCP8.5 projections. We show that, when stringent domestic emission controls are applied, air quality is predicted to improve across the US, except surface O3 over the western and central US under RCP8.5 conditions, where rising background ozone counteracts domestic emissions reductions. Under the RCP4.5, surface O3 is substantially reduced (about 5 ppb), with daily maximum 8 h averages below the primary US EPA NAAQS of 75 ppb (and even 65 ppb) in all the NPs. PM2.5 is significantly reduced in both scenarios (4 μg m−3; ~50%), with levels below the annual US EPA NAAQS of 12 μg m−3 across all the NPs; visibility is also improved (10–15 deciviews; >75 km in visibility range), although some parks over the western US (40–74% of total sites in the US) may not reach the 2050 target to restore visibility to natural conditions by 2064. We estimate that climate-driven increases in fire activity may dominate summertime PM2.5 over the western US, potentially offsetting the large PM2.5 reductions from domestic emission controls, and keeping visibility at present-day levels in many parks. Our study suggests that air quality in 2050 will be primarily controlled by anthropogenic emission patterns. However, climate and land use changes alone may lead to a substantial increase in surface O3 (2–3 ppb) with important consequences for O3 air quality and ecosystem degradation at the US NPs. Our study illustrates the need to consider the effects of changes in climate, vegetation, and fires in future air quality management and planning and emission policy making.

scholarly journals What Do Economists Have to Say about the Clean Air Act 50 Years after the Establishment of the Environmental Protection Agency?

2019 ◽  
Vol 33 (4) ◽  
pp. 3-26 ◽  
Author(s):  
Janet Currie ◽  
Reed Walker
Keyword(s):  
United States ◽  
Air Quality ◽  
Environmental Protection ◽  
Environmental Protection Agency ◽  
Clean Air Act ◽  
The United States ◽  
Economic Research ◽  
Protection Agency ◽  
The Past ◽  
Clean Air

Air quality in the United States has improved dramatically over the past 50 years in large part due to the introduction of the Clean Air Act and the creation of the Environmental Protection Agency to enforce it. This article is a reflection on the 50-year anniversary of the formation of the Environmental Protection Agency, describing what economic research says about the ways in which the Clean Air Act has shaped our society—in terms of costs, benefits, and important distributional concerns. We conclude with a discussion of how recent changes to both policy and technology present new opportunities for researchers in this area.

scholarly journals How emissions, climate, and land use change will impact mid-century air quality over the United States: a focus on effects at national parks

2015 ◽  
Vol 15 (5) ◽  
pp. 2805-2823 ◽  
Author(s):  
M. Val Martin ◽  
C. L. Heald ◽  
J.-F. Lamarque ◽  
S. Tilmes ◽  
L. K. Emmons ◽  
...  
Keyword(s):  
United States ◽  
Land Use ◽  
Air Quality ◽  
National Parks ◽  
Land Use Changes ◽  
The United States ◽  
Western Us ◽  
The Us ◽  
Emission Controls ◽  
Surface O3

Abstract. We use a global coupled chemistry–climate–land model (CESM) to assess the integrated effect of climate, emissions and land use changes on annual surface O3 and PM2.5 in the United States with a focus on national parks (NPs) and wilderness areas, using the RCP4.5 and RCP8.5 projections. We show that, when stringent domestic emission controls are applied, air quality is predicted to improve across the US, except surface O3 over the western and central US under RCP8.5 conditions, where rising background ozone counteracts domestic emission reductions. Under the RCP4.5 scenario, surface O3 is substantially reduced (about 5 ppb), with daily maximum 8 h averages below the primary US Environmental Protection Agency (EPA) National Ambient Air Quality Standards (NAAQS) of 75 ppb (and even 65 ppb) in all the NPs. PM2.5 is significantly reduced in both scenarios (4 μg m−3; ~50%), with levels below the annual US EPA NAAQS of 12 μg m−3 across all the NPs; visibility is also improved (10–15 dv; >75 km in visibility range), although some western US parks with Class I status (40–74 % of total sites in the US) are still above the 2050 planned target level to reach the goal of natural visibility conditions by 2064. We estimate that climate-driven increases in fire activity may dominate summertime PM2.5 over the western US, potentially offsetting the large PM2.5 reductions from domestic emission controls, and keeping visibility at present-day levels in many parks. Our study indicates that anthropogenic emission patterns will be important for air quality in 2050. However, climate and land use changes alone may lead to a substantial increase in surface O3 (2–3 ppb) with important consequences for O3 air quality and ecosystem degradation at the US NPs. Our study illustrates the need to consider the effects of changes in climate, vegetation, and fires in future air quality management and planning and emission policy making.

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